Hi,
On Jan 7 2016 23:14, Mark Brand wrote:
Thank you sincerely for your response, Clemens.
Please forgive my noobness, but is a full kernel compilation necessary?
I'm running Ubuntu 16.04 with 4.4.0-57-lowlatency kernel and my module
is closely based on the existing mtpav driver. I believe I know where
to place my source file, and what modifications to make to the
appropriate Kconfig and Makefile. I recall being able to specify which
modules I wanted to compile in arguments to ./configure (followed by
make modules), but I don't see that option anymore. Please, could
someone point me in the direction of a valid, step-by-step procedure?
Every set of instructions that I've been able to find seems to now be
out of date.
I use Ubuntu in my development for out-of-tree sources of ALSA firewire
stack[0].
Roughly, you don't necessarily compile a full kernel just for a few
modules, because kernel supports out-of-tree build for such modules. In
Ubuntu, 'linux-headers-xxx' package is available to build the modules
for installed kernel. In your case, it's
'linux-headers-4.4.0-57-lowlatency' package[1].
When installing this package, you can see
'/lib/modules/4.4.0-57-lowlatency/build'[2]. In each directory of kernel
source, you can build modules just included in the directory. In your case:
(Current working directory is top level of kernel source tree)
$ cd sound/drivers/
$ make -C /lib/modules/4.4.0-57-lowlatency/build M=$(pwd) snd-mtpav.ko
Of course, packages related to kernel build should be installed, for
example, installing 'kernel-package' meta package.
When success to build, you can see 'snd-mtpav.ko' in the directory.
Next, you need to put the module into a correct path for module seeking.
In rough way, replace
'/lib/modules/4.8.0-32-generic/kernel/sound/drivers/snd-mtpav.ko' with
it. The, execute 'depmod -a' to generate the latest dependency and
mapping file of installed modules.
But I don't recommend the replacement, because the original module comes
from 'linux-image-extra-4.8.0-32-generic' in Ubuntu official repository.
This way confuses package manager a bit. Therefore, it's better to make
'/lib/modules/4.8.0-32-generic/updates' directory and put the new module
into it. I don't know the reason but this directory has priority for
module seeking to the original one.
Finally, you can load the new module. It's better to check that output
of modinfo includes the new path for the module. This is a sample of my
case.
$ modinfo snd-firewire-motu
filename:
/lib/modules/4.8.0-32-generic/updates/dkms/snd-firewire-motu.ko
...
If you get used to these instructions, please investigate to apply
DKMS[3]. It will strongly help this kind of your work.
[0] https://github.com/takaswie/snd-firewire-improve
[1] http://packages.ubuntu.com/xenial/linux-headers-4.4.0-57-lowlatency
[2] as a symbolic link to '/usr/src/linux-headers-4.8.0-32-generic/'.
[3] https://github.com/dell/dkms
Regards
Takashi Sakamoto
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